[{"data":1,"prerenderedAt":387},["ShallowReactive",2],{"learn-\u002Flearn\u002Fdeclared-distances-tora-toda-asda-lda":3,"learn-nav-\u002Flearn\u002Fdeclared-distances-tora-toda-asda-lda":359},{"id":4,"title":5,"body":6,"date":290,"description":291,"draft":292,"extension":293,"faqs":294,"howTo":304,"keyTakeaways":313,"meta":314,"navigation":315,"path":316,"quiz":317,"seo":343,"series":313,"seriesOrder":313,"sources":344,"stem":356,"topic":357,"__hash__":358},"learn\u002Flearn\u002Fdeclared-distances-tora-toda-asda-lda.md","Declared distances: TORA, TODA, ASDA and LDA",{"type":7,"value":8,"toc":280},"minimark",[9,13,19,24,65,119,123,126,136,149,152,156,159,196,199,221,225,239,243,269,273],[10,11,12],"p",{},"The amount of runway you can actually use is rarely the same in every direction, or even the same for taking off and landing, which is why each runway publishes four separate distances.",[14,15,16],"blockquote",{},[10,17,18],{},"This is general educational information, not operational, legal, or regulatory advice. Rules differ by authority and change over time. Always verify against current official sources and follow your operator's approved procedures.",[20,21,23],"h2",{"id":22},"why-four-distances-not-one","Why four distances, not one",[10,25,26,27,31,32,39,40,46,47,52,53,58,59,64],{},"A runway is a strip of pavement, but the distance available to you depends on what you are doing: rolling for take-off, climbing away, stopping after a rejected take-off, or landing. To capture that, every runway direction publishes four ",[28,29,30],"strong",{},"declared distances",", defined in ",[33,34,38],"a",{"href":35,"rel":36},"https:\u002F\u002Fstore.icao.int\u002Fen\u002Fannex-14-aerodromes",[37],"nofollow","ICAO Annex 14 (Aerodromes)"," and published in the ",[33,41,45],{"href":42,"className":43},"\u002Flearn\u002Fglossary#gt-aip",[44],"glossary-link","AIP",". The same definitions appear in the ",[33,48,51],{"href":49,"rel":50},"https:\u002F\u002Fwww.faa.gov\u002Fairports\u002Fresources\u002Fadvisory_circulars\u002Findex.cfm\u002Fgo\u002Fdocument.current\u002Fdocumentnumber\u002F150_5300-13",[37],"FAA's Airport Design advisory circular (AC 150\u002F5300-13B)"," and the ",[33,54,57],{"href":55,"rel":56},"https:\u002F\u002Fwww.faa.gov\u002Fair_traffic\u002Fpublications\u002Fatpubs\u002Faim_html\u002Fchap4_section_3.html",[37],"FAA AIM",", and in ",[33,60,63],{"href":61,"rel":62},"https:\u002F\u002Fwww.easa.europa.eu\u002Fen\u002Fdocument-library\u002Fcertification-specifications\u002Fcs-adr-dsn-issue-7",[37],"EASA's aerodrome design specification CS-ADR-DSN","; ICAO, the FAA, and EASA agree on all four.",[66,67,68,80,95,108],"ul",{},[69,70,71,79],"li",{},[28,72,73,78],{},[33,74,77],{"href":75,"className":76},"\u002Flearn\u002Fglossary#gt-tora",[44],"TORA",", take-off run available."," The length of runway declared available and suitable for the ground run of an aircraft taking off.",[69,81,82,90,91,94],{},[28,83,84,89],{},[33,85,88],{"href":86,"className":87},"\u002Flearn\u002Fglossary#gt-toda",[44],"TODA",", take-off distance available."," TORA plus the length of any ",[28,92,93],{},"clearway"," beyond it.",[69,96,97,90,105,94],{},[28,98,99,104],{},[33,100,103],{"href":101,"className":102},"\u002Flearn\u002Fglossary#gt-asda",[44],"ASDA",", accelerate-stop distance available.",[28,106,107],{},"stopway",[69,109,110,118],{},[28,111,112,117],{},[33,113,116],{"href":114,"className":115},"\u002Flearn\u002Fglossary#gt-lda",[44],"LDA",", landing distance available."," The length of runway declared available and suitable for the ground run of a landing aircraft.",[20,120,122],{"id":121},"clearway-and-stopway","Clearway and stopway",[10,124,125],{},"Two pieces of ground beyond the runway end change the picture, and each helps exactly one distance.",[10,127,128,129,131,132,135],{},"A ",[28,130,93],{}," is a defined rectangular area beyond the end of the take-off run, over which an aircraft can make part of its initial climb to a screen height, kept clear of obstacles and under the control of the aerodrome authority. It lengthens ",[28,133,134],{},"TODA only",". Under EASA's aerodrome rules a clearway's length may not exceed half the take-off run available.",[10,137,128,138,140,141,144,145,148],{},[28,139,107],{}," is a defined area beyond the end of the take-off run, prepared and able to support an aircraft during a ",[28,142,143],{},"rejected take-off",". It lengthens ",[28,146,147],{},"ASDA only",".",[10,150,151],{},"Neither a clearway nor a stopway adds to TORA, because neither is runway you can roll along for a normal take-off, and a clearway is no help at all if you have to stop.",[20,153,155],{"id":154},"a-worked-illustration","A worked illustration",[10,157,158],{},"Take a runway with these published figures:",[66,160,161,167,177,186],{},[69,162,163,148],{},[164,165,166],"code",{},"TORA = 2000 m",[69,168,169,170,173,174,148],{},"a clearway of ",[164,171,172],{},"200 m"," beyond the end, so ",[164,175,176],{},"TODA = 2000 + 200 = 2200 m",[69,178,179,180,173,183,148],{},"a stopway of ",[164,181,182],{},"150 m",[164,184,185],{},"ASDA = 2000 + 150 = 2150 m",[69,187,188,189,192,193,148],{},"a displaced threshold, so landing begins ",[164,190,191],{},"100 m"," along the runway, giving ",[164,194,195],{},"LDA = 1900 m",[10,197,198],{},"Reading these, a take-off can use 2000 m on the ground and a further 200 m of clearway for the climb; a rejected take-off has 2150 m to accelerate and stop; and a landing has only 1900 m, because the displaced threshold moved the usable surface inward. Four numbers, four different distances, from one runway.",[10,200,201,202,205,206,209,210,212,213,216,217,220],{},"Now move the starting point. Suppose you take off not from the full length but from an intersection ",[164,203,204],{},"300 m"," along the runway. Your TORA falls to ",[164,207,208],{},"2000 - 300 = 1700 m",", and because TODA and ASDA are both built on TORA, they fall by the same ",[164,211,204],{},", to ",[164,214,215],{},"1900 m"," and ",[164,218,219],{},"1850 m",". The clearway and stopway beyond the far end have not changed, but everything measured from your new, later start point is shorter. That is exactly why an intersection departure must be worked on the reduced figures, never on the full-length ones printed for the runway.",[20,222,224],{"id":223},"how-each-is-used","How each is used",[10,226,227,228,231,232,234,235,238],{},"The declared distances feed your performance calculation. The ",[28,229,230],{},"take-off"," case is checked against TORA and TODA; the ",[28,233,143],{}," against ASDA, where the aircraft accelerates to a decision point and must stop within the distance available; and the ",[28,236,237],{},"landing"," against LDA. A larger aircraft's performance work balances these against each other (the balanced-field concept), while a light aircraft pilot checks the required take-off and landing distances from the flight manual against the declared distances for the conditions. The point is to compare like with like: the distance your aircraft needs against the distance the runway actually gives you.",[20,240,242],{"id":241},"common-pitfalls","Common pitfalls",[66,244,245,251,257,263],{},[69,246,247,250],{},[28,248,249],{},"Assuming the whole runway is available for everything."," A displaced threshold, a clearway, or a stopway means the four distances differ, often by hundreds of metres.",[69,252,253,256],{},[28,254,255],{},"Taking off from an intersection."," An intersection departure shortens TORA, and the reduced figure, not the full-length one, is what you have.",[69,258,259,262],{},[28,260,261],{},"Treating a clearway as stopping room."," Clearway helps the climb, not a rejected take-off; only stopway helps you stop.",[69,264,265,268],{},[28,266,267],{},"Ignoring the conditions."," Slope, surface, wind, and temperature change the distance your aircraft needs, even though the declared distances themselves are fixed.",[20,270,272],{"id":271},"in-pilot-efb","In Pilot EFB",[10,274,275,276,279],{},"Pilot EFB does ",[28,277,278],{},"not"," calculate runway performance or declared-distance margins, and it is not a certified Electronic Flight Bag. It is a study and planning aid that keeps your weather, NOTAMs, flight time, and logbook in one offline-first place. Take the declared distances from the AIP for the aerodrome, work your required distances from the approved aircraft flight manual, and follow your operator's performance procedures. Saved data stays readable offline; pulling fresh data needs a connection.",{"title":281,"searchDepth":282,"depth":282,"links":283},"",2,[284,285,286,287,288,289],{"id":22,"depth":282,"text":23},{"id":121,"depth":282,"text":122},{"id":154,"depth":282,"text":155},{"id":223,"depth":282,"text":224},{"id":241,"depth":282,"text":242},{"id":271,"depth":282,"text":272},"2026-06-02","What the four declared distances mean, how clearway and stopway extend them, and why the length of runway you can actually use is rarely just the runway.",false,"md",[295,298,301],{"q":296,"a":297},"What are TORA, TODA, ASDA and LDA?","They are the four declared distances published for each runway direction. TORA is the take-off run available, TODA is the take-off distance available, ASDA is the accelerate-stop distance available, and LDA is the landing distance available. ICAO Annex 14 defines them and they are published in the AIP for each aerodrome.",{"q":299,"a":300},"What is the difference between a clearway and a stopway?","A clearway is a defined area beyond the runway over which an aircraft can make part of its initial climb, and it extends only the take-off distance available (TODA). A stopway is a defined area beyond the runway able to support an aircraft during a rejected take-off, and it extends only the accelerate-stop distance available (ASDA). Neither lengthens the take-off run available.",{"q":302,"a":303},"Why might the landing distance available be shorter than the runway?","If the threshold is displaced, the usable landing surface starts some way along the runway rather than at its physical end, so the landing distance available (LDA) is shorter than the full runway length. Obstacles, declared distances at an intersection, or works can also reduce the distance you can actually use.",{"name":305,"steps":306},"How to read the declared distances for a runway",[307,308,309,310,311,312],"Find the declared distances for the runway direction you will use, published in the AIP entry for that aerodrome.","Read TORA, the runway length available for the take-off ground run.","Read TODA, the take-off distance available, which is TORA plus any clearway beyond it.","Read ASDA, the accelerate-stop distance available, which is TORA plus any stopway beyond it.","Read LDA, the landing distance available, which may be shorter than the runway if the threshold is displaced.","Compare each declared distance against your aircraft's required take-off, accelerate-stop and landing distances for the conditions.",null,{},true,"\u002Flearn\u002Fdeclared-distances-tora-toda-asda-lda",[318,327,335],{"q":319,"options":320,"answer":325,"explanation":326},"What does a clearway beyond the end of the runway extend?",[321,322,323,324],"The take-off run available (TORA)","The take-off distance available (TODA) only","The accelerate-stop distance available (ASDA) only","The landing distance available (LDA)",1,"A clearway is a defined area beyond the runway over which an aircraft can make part of its initial climb, and it lengthens TODA only. It adds nothing to TORA, ASDA, or LDA.",{"q":328,"options":329,"answer":282,"explanation":334},"Why can the landing distance available (LDA) be shorter than the full runway length?",[330,331,332,333],"Because a clearway shortens the usable surface","Because a stopway is reserved for rejected take-offs","Because a displaced threshold moves the usable landing surface inward","Because TODA and ASDA are subtracted from it","If the threshold is displaced, landing begins some way along the runway rather than at its physical end, so the LDA is shorter than the full runway length.",{"q":336,"options":337,"answer":325,"explanation":342},"Taking off from an intersection 300 m along a runway whose TORA is 2000 m has what effect on TORA, TODA and ASDA?",[338,339,340,341],"TORA falls to 1700 m, while TODA and ASDA stay the same","TORA, TODA and ASDA each fall by 300 m","Only TORA falls; TODA and ASDA rise by 300 m","None of them change, because the clearway and stopway are unchanged","TORA falls to 2000 - 300 = 1700 m, and because TODA and ASDA are both built on TORA they fall by the same 300 m. An intersection departure must be worked on the reduced figures.",{"title":5,"description":291},[345,347,349,352,354],{"label":346,"url":35},"ICAO Annex 14: Aerodromes",{"label":348,"url":61},"EASA CS-ADR-DSN (Aerodrome Design)",{"label":350,"url":351},"EASA Easy Access Rules for Aerodromes","https:\u002F\u002Fwww.easa.europa.eu\u002Fen\u002Fdocument-library\u002Feasy-access-rules\u002Feasy-access-rules-aerodromes-regulation-eu-no-1392014",{"label":353,"url":49},"FAA Advisory Circular 150\u002F5300-13B: Airport Design",{"label":355,"url":55},"FAA Aeronautical Information Manual, 4-3-6 (Use of Runways \u002F Declared Distances)","learn\u002Fdeclared-distances-tora-toda-asda-lda","Operations","HxmXgPtdOtvH5nQWJjkb8Bl_Qq0Wjg9JTW0mYEKO9ho",{"related":360,"newer":376,"older":381,"series":313},[361,367,371],{"path":362,"title":363,"description":364,"date":365,"topic":357,"draft":292,"minutes":366,"series":313,"seriesOrder":313},"\u002Flearn\u002Fcold-temperature-altimeter-corrections","Cold-temperature altimeter corrections","Why a pressure altimeter over-reads in cold air, leaving you lower than indicated, and how to correct minimum altitudes for temperature on an approach in mountainous or freezing conditions.","2026-06-21",4,{"path":368,"title":369,"description":370,"date":365,"topic":357,"draft":292,"minutes":366,"series":313,"seriesOrder":313},"\u002Flearn\u002Fmode-s-and-ads-b-explained","Mode S and ADS-B explained","How Mode S adds a 24-bit address, selective interrogation and a data link to the transponder, the difference between elementary and enhanced surveillance, and how ADS-B broadcasts your GPS position.",{"path":372,"title":373,"description":374,"date":365,"topic":357,"draft":292,"minutes":375,"series":313,"seriesOrder":313},"\u002Flearn\u002Fthe-global-reporting-format-for-runway-conditions","The Global Reporting Format for runway conditions","How the Global Reporting Format (GRF) describes a contaminated runway, including the runway condition code (RWYCC) from 6 to 0, the assessment matrix (RCAM), and how the report is split into thirds.",5,{"path":377,"title":378,"description":379,"date":380,"topic":357,"draft":292,"minutes":366,"series":313,"seriesOrder":313},"\u002Flearn\u002Fmass-and-balance-basics","Mass and balance basics","What datum, arm, moment and centre of gravity mean, how to work a centre-of-gravity calculation step by step, and why staying inside the envelope matters as much as staying under the maximum mass.","2026-06-03",{"path":382,"title":383,"description":384,"date":385,"topic":357,"draft":292,"minutes":366,"series":386,"seriesOrder":375},"\u002Flearn\u002Fcrosswind-components","Crosswind components","How to resolve a reported wind into its crosswind and headwind components with simple trigonometry, a worked example, the sine rule of thumb, and what a maximum demonstrated crosswind really is.","2026-06-01","plan-a-vfr-cross-country",1781989190786]